ANALYSIS AND DESIGN IMPROVEMENTS OF A HIGH PRECISION KINEMATIC MECHANISM

A new design for reducing the kinematic mechanism error is presented in this paper. Firstly, a prototype having a universal joint is presented and the kinematic model in the Simmechanics environment of Mat lab is described, studying the system behaviour by means of simulation. Then, the manufacturing and assembly of the platform is performed and the mechanism performance is evaluated. To do this, different tests are carried out in which the mechanism backlash and the influence of the elevation angle and the misalignment in every axis due to backlash are analyzed. Finally, the mechanism design is improved by replacing the universal joint with a new element that consists on bearings and precision locknuts. This element allows us to obtain the two desired degrees of freedom. The replacement of the commercial universal joint by the developed element implies a considerably increment of the mechanism accuracy. The developed platform has many applications in the industry, such as, machining tool processes, high range metrology, holder base for measurement tools such as topography instruments, mirror orientation in telescopes, etc.